The Science of The Science of BiologyBiology

Chapter 2Chapter 2

What is Science??What is Science?? Science (“to know”) is a way to ask Science (“to know”) is a way to ask

questions about the natural worldquestions about the natural world Science is testable or falsifiable; beliefs, Science is testable or falsifiable; beliefs,

opinions, and the supernatural are not opinions, and the supernatural are not testabletestable

Science is supported with evidence that Science is supported with evidence that can be verified through repeated can be verified through repeated experimentsexperiments

What is Science?? What is Science?? (continued)(continued)

Science is Science is NOTNOT a set of unchanging facts; it is a set of unchanging facts; it is an ongoing process that advances knowledge an ongoing process that advances knowledge and understandingand understanding

Scientific knowledge is uncertainScientific knowledge is uncertain Reality is complexReality is complex Explanations of reality are not absolutely trueExplanations of reality are not absolutely true Allows for alternative explanations to better explain Allows for alternative explanations to better explain

observationsobservations Scientists must be skeptical (question existing Scientists must be skeptical (question existing

ideas) and open-minded (consider new ideas) and open-minded (consider new hypotheses if the data supports it)hypotheses if the data supports it)

Discovery ScienceDiscovery Science

Describes natural structures or Describes natural structures or processes through careful observation processes through careful observation and data collectionand data collection

Emphasizes inquiry and observationEmphasizes inquiry and observation InquiryInquiry is about asking questions is about asking questions

based on observations and actively based on observations and actively seeking answersseeking answers

ObservationObservation is the use of the is the use of the senses or instruments to gather and senses or instruments to gather and record information about structures or record information about structures or processesprocesses

Observations are recorded as Observations are recorded as DataData

Types of DataTypes of Data

QUANTITATIVEQUANTITATIVE

A recorded A recorded measurementmeasurement

Scientists worldwide use Scientists worldwide use the metric systemthe metric system

QUALITATIVEQUALITATIVE

Descriptions, drawings, Descriptions, drawings, or photographsor photographs

Best data is Best data is documented, clearly documented, clearly organized, consistently organized, consistently recorded, and reliablerecorded, and reliable

InferencesInferences

Logical conclusions Logical conclusions based on observationsbased on observations

Example:Example:In 1928, Alexander Fleming In 1928, Alexander Fleming

observedobserved a mold a mold contaminating a cultured contaminating a cultured of bacteria. He noticed of bacteria. He noticed no bacteria growing near no bacteria growing near the mold.the mold.

He He inferredinferred that the mold that the mold was killing the bacteria.was killing the bacteria.

Practice making Practice making Inferences…Inferences…

Inferences and Inferences and Generalizations in Generalizations in ScienceScience

Inferences help refine general questions into Inferences help refine general questions into specific questions that can be explored furtherspecific questions that can be explored further

Ex: Ex: What substance produced by this What substance produced by this mold is killing the bacteria?mold is killing the bacteria?

Generalizations are conclusions formed from Generalizations are conclusions formed from many specific observations that are relatedmany specific observations that are related

Ex: Ex: Many molds have antibiotic Many molds have antibiotic properties that can be used to kill bacteria properties that can be used to kill bacteria harmful to humans.harmful to humans.

Hypothesis-based Hypothesis-based Science Science

Seeks explanations to Seeks explanations to specific questions by specific questions by testing predictionstesting predictions

Ex: Poisonous snakes have Ex: Poisonous snakes have bright colors and rings. bright colors and rings. Some non-poisonous Some non-poisonous snakes also have bright snakes also have bright colors and rings.colors and rings.

Question: What is the Question: What is the function of such mimicry?function of such mimicry?

POISONOUS

NON-POISONOUS

Form a HypothesisForm a Hypothesis

Hypothesis: Mimics benefit because predators confuse Hypothesis: Mimics benefit because predators confuse them with the harmful species.them with the harmful species.

Restate the hypothesis in “IF, AND, and THEN” format:Restate the hypothesis in “IF, AND, and THEN” format:IfIf this idea is true, this idea is true, andand I do this, I do this, thenthen this will happen. this will happen.

EX:EX:IfIf predators confuse the mimics with the harmful predators confuse the mimics with the harmful species, species, andand I expose predators to non-poisonous I expose predators to non-poisonous snakes with rings and without rings, snakes with rings and without rings, thenthen the predators the predators will attack the species without the rings more often. will attack the species without the rings more often.

Design a Controlled Design a Controlled ExperimentExperiment

The experiment is designed to test the hypothesisThe experiment is designed to test the hypothesis Can only test the effect of ONE variable!!Can only test the effect of ONE variable!!

Ex: The presence of colored rings on the snakes bodyEx: The presence of colored rings on the snakes body

The Control Group The Experimental Group

Organize Data and Organize Data and Interpret ResultsInterpret Results

Quantitative data Quantitative data should be organized should be organized into charts and into charts and graphsgraphs

The results will either The results will either support the support the hypothesis or cause hypothesis or cause the scientist to revise the scientist to revise his or her hypothesis his or her hypothesis and test againand test again

0

20

40

60

80

100

Brown Ringed

Theories in ScienceTheories in Science

A theory is a well-tested explanation that makes A theory is a well-tested explanation that makes sense out of a great variety of scientific sense out of a great variety of scientific observationsobservations

Supported by an extensive body of evidenceSupported by an extensive body of evidence Provide framework for future research and Provide framework for future research and

predictionspredictions Subject to modification as new evidence is Subject to modification as new evidence is

uncovereduncovered

Models in ScienceModels in Science

Models are physical, mental, or mathematical Models are physical, mental, or mathematical representations of how to understand a process or an representations of how to understand a process or an idea idea

Can be drawings, graphs, 3D, computer programs, or Can be drawings, graphs, 3D, computer programs, or equationsequations

Communication and Communication and Technology in ScienceTechnology in Science

Communication is necessary for cooperation Communication is necessary for cooperation and competition among scientistsand competition among scientists

Scientist communicate their ideas in published Scientist communicate their ideas in published journals and the webjournals and the web

Technology is the result of applied scientific Technology is the result of applied scientific understandingunderstanding

Ex: Structure of DNA = ScienceEx: Structure of DNA = Science

Genetic Engineering = Technology Genetic Engineering = Technology

Science, Technology, and Science, Technology, and SocietySociety

Technology is not driven by the curiosity that Technology is not driven by the curiosity that drives basic science, but by the needs and drives basic science, but by the needs and wants of humanswants of humans

Ethics in Science: Debated issues about Ethics in Science: Debated issues about technology ask “technology ask “shouldshould it be done,” not “ it be done,” not “cancan it it be done”be done”

Good citizens make an effort to understand the Good citizens make an effort to understand the technology before making lifestyle and technology before making lifestyle and democratic choicesdemocratic choices